Joint



W. R. ROPER Jam 29, 1957 JOINT 2 Shets-Sheet 1 Filed June 12, 1953 A TTORNE Y5 Wm WW/M m JOINT Winston R. Roper, Houston, Tex., assignor to Houston Oil Field Material Company, Inc., Houston, Tex., a corporation of Delaware Application June 12, 1953, Serial No. 361,289

Claims. (Cl. 255-1.6)

. This invention relates to a joint for connecting parts of a drill string, and, more particularly, relates to a joint used in the directional drilling of well bores and the like.

In drilling oil, gas and other wells, many times it is desirable to change the direction of the well bore from that originally drilled or to intentionally drill a directional hole at the outset. In order to accomplish this, a number of directional drilling tools are available, among which is the whipstock which may be lowered into a well bore, oriented in the direction desired to be drilled and set in place for drilling down along the general direction of the face of the whipstock. Ordinarily, whipstocks have a collar at the upper end, the bit, or drill collars and bit, being suspended below the collar which engage the collar in order that the whipstock may be retrieved from the well bore upon elevating the string of pipe to which it is connected, after drilling the desired distance. This permits the whipstock to be set, a desired section of hole to be drilled and the whipstock removed with the drill assembly, all in one trip in the well bore.

To facilitate drilling off the face of whipstocks or substantially increasing the angle at which drilling might be accomplished, universal type joints connecting parts of the drill string have been developed which are of small enough external diameter to pass through the collar of the whipstock. These are generally known in the trade as slim joints.

In view of the confining space through which the slim joint must pass, it is extremely difficult to provide a universal joint of this character which is strong and rugged for satisfactory use in drilling oil wells and the like.

It is therefore a major object of the present invention to provide a slim joint for connecting parts of a drill string which is strong and rugged, dependable in operation, and yet will readily pass through a confined space, such as the collar of a whipstock.

It is yet a further object of the present invention to provide such a joint which is economical to manufacture and maintain, and which may readily be repaired or have parts replaced.

In the drilling of oil wells and the like by the rotary.

method, fluid, commonly known as drilling mud, is circulated in the well bore and, many times, the circulating mud will foul universal-type joints connecting parts of the drill string.

It is, therefore, a further object of the present invention" to provide a slim joint of the above character which will not foul in use, but which has the tiltable driving elements of the joint sealed from well fluid circulating the drill string and well bore. -It is a feature of the present invention to provide a maximum amount of engageable surface of the driving keys and keyways, in order to transmit rotation from one section of the joint to the other. I

Other and further objects and features will be apparent from the following description of an example of the inventiongiven for the purpose of disclosure, taken in connection with the accompanying drawings, where like refer- ICQ ence characters designate like parts throughout the several views, and where,

Figure l is a side elevation of a slim joint constructed in accordance with the invention and illustrated as drilling off the face of a conventional whipstock, after the whipstock has been set in the well bore,

Figure 2 is an exploded view of elements of a slim joint constructed in accordance with the invention,

Figure 3 is a fragmentary elevation, in section, of the slim joint illustrated in Figure 2,

Figure 4 is a cross-sectional view taken along the line 4-4 of Figure 3, and

Figure 5 is a perspective view of a driving key of the slimjoint.

Referring now to the drawings, and particularly to Figure 1, the slim joint is designated generally by the reference numeral 1 and serves as a universal or tiltable connection between the string of pipe 2 which extends to the surface (not shown) by which the joint is suspended in the well bore and the drill string 3, to the lower end of which the bit 4 is threadedly or otherwise secured. As

, illustrated, if desired, drill collars 5 may be provided above the bit to provided added weight to the bit; al-

though, these drill collars may be omitted. Also, as illustrated, the drill pipe 3 may be threaded to the slim joint 1 by means of the conventional tool joint or substitute 6 which is of a size sufficient to pass through the collar 7 invention. As illustrated, however, the slim joint 1 is of a size which will readily pass through the collar 7 of the whipstock 8 in order that the bit 4 may drill in the desired direction down along the face of the whipstock 8. As is customary, the drill collar 5 or bit 4, or both, may be of a greater size than the internal diameter of the collar 7 of the whipstock 8 so that upon elevating the drill pipe 2, the drill collar 5 or bit 4 will engage the underside of the collar 7 and the whipstock retrieved from the well bore along with the drill string assembly.

Referring now to my novel slim joint, and particularly to Figure 3 of the drawings, the slim joint 1 includes the hollow body member 10, which may be substantially tubular, into the lower end of which is inserted the thrust plate 12 which is held in position by means of the pin 14 of the drill pipe 3 (see Figure l) threaded in the lower portion of the body 10. The upper surface 17 of the thrust plate 12 is a socket element and is a concave seat or bearing surface of a substantially spherical sector.

Extending downwardly into the central portion of the body 10 is the ball stem or mandrel 18, the lower end of which forms a ball element which includes the convex bearing surface 19 which is substantially a spherical sector and forms a segment of a ball connection which engages the surface 17 of the thrust plate 12.

The body 10 has the downwardly-facing concave annular seat 20 which is spaced upwardly from the surface 17 of the thrust plate 12 into which is seated the upwardlyfacing-shoulder or hearing means 22 of the ball stem which is complementary thereto. The ball element has the greatest diameter at the lower portion of the shoulder 22, as at 24 (see Figure 2) and its sides 25 converge downwardly to the lower bearing surface 19 at the bottom of the ball stem 18. Thus, a tilting or rocking connection is provided with a pivot point substantially about the portion indicated by the numeral 24. i p

In order to transmit rotation from the string of pipe 2 above the; joint to the bit 4 there below, the driving keys 26 are provided in the body 10. These may be provided in any suitable manner; however, a satisfactory arrangement is illustrated in Figure 4. As best seen in Figures 2 gamma and 4, the driving keys 26 are removably placed in the.

windows 28 of the body iii. The upper and lower portions of the body 16 adjacent the windows 28 are recessed, as at 38, (see Figure 3)- to receive the shoulders 32 disposed at each end of the driving keys 26. The body 10 is further recessed at each side of the windows 28, as at 34 and each driving key 26 is recessed at 36, which'recess: is in registry with the recesses 34. The straps 38 are provided which tit in the recessed portions 34 and 36 of the body 10 and the driving keys 28 respectively, the straps being securely held in place by means of the metal screws 41 It is noted that the straps 22 are set flush with the exterior surface of the body 28 to provide a smooth outer surface. While any suitable arrangement may be utilized for providing driving keys in the body 10, the arrangement illustrated is satisfactory and the individual keys may readily be removed and replaced to facilitate maintaining and repairing the joint.

The keys 26 are provided with the inwardly-extending portions 42 which have the downwardly-converging sides 44 and the upwardly converging sides 4-8 extending from the point indicated by the numeral 46. These sides are inclined at substantially the angle from the axis of the joint at which the joint tilts in order that a maximum amount of material may be provided in the driving keys and a maximum amount of surface of the keys is engageable by the keyways 50' formed in the upper end of the ball stem 18, as will be apparent later.

The keyways 59 receive the driving portions 42 of the keys 26 and extend a distance greater both laterally and longitudinally than the driving portions 42 of the keys 26, although a rather close fit is provided proximate the por tion 46 of the keys 26. The length of the keyways or slots 58 should be suflicient to permit complete rocking of the stem 18 in the body 18, and this will vary with the size of n sides 52 of the keyways 50 engage the entire sides 44 and,

48 of the driving portions 42 of the keys 26 during portions of a complete revolution, yet at the point of tilting,

the keys are of maximum width to provide strength to,

the joint which must be constructed strong enough to withstand normal drilling loads and at the same time be;

small enough to be moved through confined spaces. Thus, a tilting or rocking movement throughout a relatively highiangle is provided, whichat the sametime, pro .v vides a maximumamount of strength to transmit rotation fromjthesocket element to the ball element.

' In order to provideadded stability to the joint during the rockingor tilting movement of the ballandsocket; elementa the upper inner surface 54 of thebody 10 is; downwardly converging which coacts with the outer SllIfface of the ball. stem 18, and which is provided at the, angle through which the tiltable connection is meant to operate, thereby providing support and stability; to the connection, as best seen inFigureB,

rderfto; pre e i fl id. qmenter ng. he;ii11tand'f fouling the, connection, a shroud sleeve 56; is;.p ro-,. vid'ed whichiyieldingly engages the upper end 58, of the-1 bodyflt). As seen in Figure 3, thelower surface 60 of the shroud sleeve 56 and the surface 58 are complemenf tary and are generally annular sectors of spheres to permit ease of rotation of the ball stern'with' respect to the body and at the same time prevent drill fluid in appreciable amounts from entering into the connection and fouling the .same.

In; order that the. sleeve 56 may yieldingly' be urged intosliding contact with the upper surface 58 of thebody 10, the sleeve56 is counterboredat 62 toprovide' theupwardly-facing internal annular shoulder 64. The

compression spring. 66 is provided about the ball stem. 18 and in the counterbored portion 62 and the lower end stops against the upwardly-facing shoulder 64, thereby urging the sleeve downwardly. A retaining nut 68 is threaded to the ball stem 18 which has the downwardlyfacing annular shoulder '70 to engage the upper portion of the compression spring 66. If desired, a locking nut 72 may be threaded about the ball stem 18, as illustrated in Figure 3,, to lock the retaining nut 68 in place.

It is customary in the drilling of oil wells by therotary method to circulate drill fluid, and for this purpose, a passage 74 is provided in the ball stem 18 which is in fluid communication with the passage (not shown) inthe drill string 2. The passage '74 is in communication with the passage '76 in the thrust plate 12, which latter passage is upwardly and outwardly flared, as at 78, in order to be in registry with the lower end of the passage 74 throughout the complete revolution of maximum tilting. The fluid passage '76 registers with a passage in the pin 14, which in turn, registers with the passage (not shown) in the drill pipe 3. Thus, drill fluid or mud is circulated through the string of pipe 2, the tiltable connection 1, down through the drillpipe 3-, the drill collar 5 and out the bit- 4 in the usual manner. As illustrated, suitable packing may be provided to prevent leakage of drill fluid from these passages into the joint, such as providing thev O-rings 82 and 84 at the upper ends of the pin 14' and thrust plate 12 respectively. While the arrangement illustrated is satisfactory, any suitable packing arrangement may be utilized.

The tiltable connection or joint 1 may be assembled by placing the upper end of the ball stem 18 in the lower end of the body 10 and moving it upwardly until the surface 22 thereon seats in the surface 20 in the body 10. The keys 26 may then be placed in the body 10 and aligned with. the keyways 50 in the ball stem element 18, and secured in, place by placing the straps 38 in position. and threading the screws 40 in, place. The thrust plate 12 may then be moved. into position in the lower end of the body 10 and the pin 14 of a suitable tool joint. The shroud sleeve 56 may be positioned about the ball stem18, the compression spring. 66 inserted between the. stem 18 and the shroud sleeve 56, and the nuts 68 and. 7,2 threaded into position. The tiltable joint is then in assembled positionand ready to be threaded into a string oi pipefor use.

While the tiltable connection or joint may be used in, anumber of ways and for a number of purposes, as an example of a typical use of the joint, the joint may be. provided in a string of. pipe to whichis secured the whipstock 8. Ordinarily and conventionally, either. the bit. 4 or the drill collar 5 is secured to the collar 7 of the. whipstock by means of a shear pin, not shown, so that the whipstock may be lowered into the well bore, the, faceof the whipstock oriented in, order that drilling may take place in the desired direction, and by applyinga. downward. force on the string of pipe 2, the shear pin is. sheared, permitting the bit to drill down along, the

face, of the whipstock 8 and in the intended direction and.

angle, as illustratedin Figure 1. Thisvis conventional,

practice and no detailed description thereoi is, d eemed,-

8, but at the same time, a rugged tiltable connection. or.

joint is... provided, in that a considerable extentof the ball stem.18.is in engagement withrand supported by; the sides 52 of the keys 26,. and also in contact with .the inner surface 5j4'of the body 10, and a maximum width of the driving portions 42 of the keys 26 is provided'thereby the drilling operation, of course, rotation, is;

providing stability for the connection. Also, fouling of the tiltable joint is prevented by means of the arrangement illustrated. During such drilling, drill fluid is circulated through the string of pipe, slim joint and out the bit in the usual manner.

After drilling a desired distance, the pipe 2 may be elevated at the surface, thereby elevating the bit 4, moving the tiltable connection 1 upwardly through the collar 7 and either the drill collar 5 or bit 4 engaging the underside of the collar 7 of the whipstock 8 whereby the whipstock may be removed from the well bore in the usual manner.

It should be noted that substantially the entire downward thrust of the connection is taken by the bearing surfaces 17 and 19 of the thrust plate 12 and the lower end of the ball stem element 18, respectively, with no downward thrust being applied to the keys 20, thereby reducing the possibility that the keys will be sheared. Also, in addition, during the rotation of the joint in a tilting movement, the full sides 44 of the keys 26 engage the sides 52 of the keyways 50 during at least a portion of the rotation, thereby providing more surface to transmit the torque force. Additionally, the large side surfaces 44 and surfaces 48 of the driving portions 42 of the keys engage the sides 52 of the keys 50 to provide considerable surface for transmitting rotation from the body to the ball stem 18. Thus, shearing of the keys 25 is minimized and great stability is provided for the .tiltable joint although it is of reduced external diameter to the extent suflicient to permit it to pass readily through the collar 7 of the whipstock 8.

As indicated previously, the arrangement prevents drill fluid from coming into contact with the working parts of the tiltable joint thereby preventing fouling of the connection.

While the slim joint is satisfactory when used as indicated, satisfactory results have been obtained by reversing the position of the parts, and the joint may be satisfactorily run in either position.

It is apparent that the joint of the present invention is one which fulfills the objects set forth and other objects inherent therein. While only a single example of the present invention is given for the purpose of disclosure, it will be obvious to those skilled in the art that various changes and rearrangements of parts may be made within the spirit of the invention. Accordingly, it is desired to be limited only by the spirit of the invention and the scope of the appended claims.

What is claimed is:

1. A joint for connecting parts of a drill stem and adapted to be moved through confined spaces comprising; a socket assembly including a tubular body adapted to be secured to the drill stem; a socket in the body, said socket comprising a thrust plate having an upwardly-facing curved concave seat, an annular downwardly-facing curved concave seat in the body spaced from said thrust plate; a ball stem assembly including a stern extending downwardly into the body, said stem including a ball element, said ball element comprising a downwardlyfacing convex curved portion at its lower end cooperating with and seating in the first-mentioned seat, said stem being upwardly and outwardly flared from its lower end, the flared portion terminating in at least one upwardlyfacing convex seat cooperating with and seating in the secondmentioned seat; the inner diameter of the body below the second-mentioned seat being greater than the outer diameter of that portion of the ball stem extending below the second-mentioned seat; said ball and socket elements forming a ball and socket connection; interfitting enlongated keys and keyways on the body and the ball element for transmitting rotation from the ball stem assembly to the socket assembly; said keyways being of greater length than said keys, said keys having tapered sides extending downwardly at an angle to the axis of the body, the sides of said keys adapted to engage sides of sa d keyways f r transm g s h rotatio the p: p r inn portion of e body ei g up r y and cut wardly flared at substantially the same angle to itsaxis as that of the tapered sides whereby on maximum tilting of the body relative to the stem the outer surface of the stem engages the outwardly-flared portion of the body and at least one of the sides of the keys engages the side of its companion keyway substantially along the length of its downwardly tapered portion; and registering fluid passageways through said body, thrust plate and said ball stem assembly.

2. The joint of claim 1 including a shroud ring disposed about said stern and above said body, resilient means supported about said stem and inside said shroud ring for resiliently holding the lower face of said shroud ring against the upper face of said body, said faces being curved and complementary to one another.

3. A joint for connecting parts of a drill stem and adapted to be moved through confined spaces comprising; a tubular body adapted to be secured to the drill stem; a socket in the body, said socket including a thrust plate having an inwardly-facing curved concave seat, a .concave seat in the body spaced from and facing toward said thrust plate; a ball stem adapted to be secured to the drill stem and extending into the body, said stem including a ball element comprising a convex spherical sector at one end engaging and cooperating with the firstmentioned seat, said stem being outwardly-flared from its said one end and terminating in an outwardly-facing convex-bearing means cooperating with and seating in the second-mentioned seat; the inner diameter of the body between the two seats being greater than the outer diameter of that portion of the ball stem between said two seats; said ball and socket elements forming a tiltable connection; and interfi-tting keys and keyways on the body and ball element, the interfitting portions of the keys having sides tapering at an angle to the axis of the body toward the thrust plate, and the keyways being substantially greater in length than that of said keys; the inner portion of the body beyond the second-mentioned seat being outwardly inclined at substantially the same angle to the axis of the body so that of the tapered sides whereby on maximum tilting of the body relative to the stem the outer surface of the stem engages the outwardlyflared portion of the body and at least one of the sides of the keys engages the side of its companion keyway substantially along the length of its tapered side.

4. The joint of claim 3 where the keys are removably disposed in the body.

5. The joint of claim 3 including registering fluid passages in the body, thrust plate, and ball stem for circulating drill fluid through the joint, a shroud sleeve disposed about the ball stem beyond the body, the surface of one end of the shroud sleeve engaging the adjacent surfacce of the body, said surfaces being complementary, and spring means disposed between the ball stem and shroud sleeve and bearing against said ball stem and shroud sleeve for resiliently urging said surfaces against one another.

6. The joint of claim 5 including seal means interposed between the thrust plate and the said one end of the ball stem.

7. A joint for connecting parts of a drill stem and adapted to be moved through con-fined spaces comprising; a tubular body adapted to be secured to the drill stem; a socket in the body, said socket including a thrust plate having an upwardly-facing curved. concave seat, a downwardly-facing curved concave seat in the body spaced upwardly from said thrust plate, said concave seat provided with a passage through its central portion; a ball stem adapted to be secured to the drill stem and extending downwardly into the body and through the passage, said stem including a ball element comprising a convex spherical sector at its lower end engaging and cooperating with the first-mentioned seat, said stem being upwardly and outwardly flared from its lower end and terminating in an upwardly-facing convex bearing means cooperating with and seating in the second-mentioned seat; said socket and ball element forming a tiltable connection; and interfitting keys and keyways on the body and ball element, the interfitting portions of the keys having downwardly-tapering sides and the keyways being substantially greater in length than that of said keys; the upper inner portion of the body being upwardly and outwardly inclined at substantially the same angle to its axis as that of the downwardly tapering sides whereby on maximum tilting of the body relative to the stem the outer surface of the stern engages the outwardly flared portion of the body and at least one of the sides of the keys engages the side of its companion keyway substantially along the length of its downwardly tapered portion.

8. The joint of claim 7 where the keys are removably ably disposed in the body.

9. The joint of claim 7 including registering fluid passages in the body, thrust plate and ball stem for circulating drill fluid through the joint, a shroud sleeve disposed about the ball stem above the body, the lower surface of the shroud sleeve engaging the upper surface of the body, said surfaces being complementary, and spring means disposed between and bearing against the ball stem and shroud sleeve for resiliently urging said faces against one another.

10. The joint of claim 9 including seal means interposed between the thrust plate and the lower end of the ball stem.

References Cited in the file of this patent 3 UNITED STATES PATENTS 1,841,418 Scott Jan. 19, 1932 2,010,587 Fisher et al. Aug. 6, 1935 2,114,807 McCavitt Apr. 19, 1938 2,194,267 Brock et a1. Mar. 19, 1940 2,266,383 Quintrell Dec. 16, 1941 2,291,100 Oswald July 28, 1942 2,304,119 Potts Dec. 8, 1942 2,667,332 McCune et al. Jan. 26, 1954 FOREIGN PATENTS 364,766 France Aug. 28, 1906 

